Native Collada Support

Collada is a format which supports (almost) anything a game would ever need, contrary to the .egg format which does not support a lot of essential things.
As collada is a format which is supported by most modeling tools, it is an essential feature to Panda. We currently have a dae2egg already, but as it is limited by the .egg format, it is not very useful for entire scenes.
Therefore I think it would be a great feature to natively load and save .dae files.